its an xj thing
NAXJA Forum User
- Location
- Wisconsin
my 98 4.0 has had a rough idle and low mpg since i bought it. i checked the 02 sensors with a obd2 scanner and looked at live data graphes to see what they were doing.
the pre cat 02 sensor seemed to be changing voltage quickly and consistently while the downstream sensor was pretty lazy.
i unplugged the upstream sensor to see how it would affect the drive-ability and the only thing that changed was the check engine light came on. absolutely no difference in running or driving.
would this indicate the upstream sensor is bad? i bought a new one just in case, but would like some input on what others think.
the pre cat 02 sensor seemed to be changing voltage quickly and consistently while the downstream sensor was pretty lazy.
i unplugged the upstream sensor to see how it would affect the drive-ability and the only thing that changed was the check engine light came on. absolutely no difference in running or driving.
would this indicate the upstream sensor is bad? i bought a new one just in case, but would like some input on what others think.